When an application opens a file stored on a NAS storage for modification, it is the responsibility of the application to calculate the changes made to the file and send only the changes to the storage. However, some applications may send to the storage the entire file, as if the entire file was changed, even if only a small portion was changed.
Storage systems consume vast amount of storage and computing resources for tracking changes. For example, a journal file that records transactions will consume increased storage resources for recording write requests of larger size, since the data to be written is temporarily stored in the journal file.
An asynchronous remote mirroring will waste computing resources and probably storage resources for calculating differences occurred since a previous replication cycle in a volume or file system to be replicated, when the amount of differences is prominent.
Snapshots will consume extra storage resources when there are more differences occurred since a previous snapshot has been taken.
Other processes that will suffer from extensive updates include CDP (Continuous Data Protection), that automatically saves a copy of every change made to data and incremental processes, such as incremental backup and incremental virus scans.
Thus, if an application rewrites unchanged data, not only unnecessary rewrites of the unchanged data are performed in vain, but it also affects performance of other processes that are difference-driven